[Ifeffit] How to use "OVERLAP" card?

Bruce Ravel bravel at anl.gov
Tue May 8 08:37:10 CDT 2007


Hi Jun,

That keyword is explained here:

  http://feff.phys.washington.edu/feff/wiki/index.php?title=OVERLAP

I think the problem is that you have not specified the SS keyword:

  http://feff.phys.washington.edu/feff/wiki/index.php?title=SS

I use the overlap/ss thing in feff very infrequently.  My preference
is to start from a known structure that is somehow similar to the
material I am investigating.  For example, if I were to look at
amorphous germanium, I would use crystalline germanium as my starting
point.  I would then construct the model in such a way that I
parameterize the differences between the starting structure and what I
expect to find in the data.

I'd recommend reading papers by Scott Calvin or Anatoly Frenkel on
nanoparticles or by Shelly Kelly on uranium in biogeochemical systems
for excellent examples of how that sort of analysis is done.

Hope that helps,
B



On Tuesday 08 May 2007, Jun Lin wrote:
> Hi everybody:
>
> It is the first time I send mail to this list.
>
> I wanna use OVERLAP of Feff8.4 to design a structure for my analysis, but
>
> the program give error message as followed:
>  > Feff 8.40
>  > OVERLAP:
>  > Expert option, please read documentation carefully and check your
>
> results.
>
>  > OVERLAP:
>  > Expert option, please read documentation carefully and check your
>
> results.
>
>  > My test for OVERLAP
>  > Absorbing atom coords not specified.
>  > Cannot find multiple scattering paths.
>  > RDINP
>  > STOP   statement executed
>
> in my feff.inp, I wrote like this:
>       TITLE My test for OVERLAP
>       *         pot    xsph  fms   paths genfmt ff2chi
>      CONTROL   1      1     1     1     1      1
>      PRINT     0      0     0     0     0      0
>      POTENTIALS
>      *    ipot   Z  element            * l_scmt  l_fms   stoichiometry
>             0   26   Fe
>             1   7    N
>      OVERLAP 0
>         0    1    0.00
>         1    4    1.15
>      END
>
> Is there anyone give me some suggestion? Thanks!
>
> Lin Jun



-- 
 Bruce Ravel  ---------------------------------------------- bravel at anl.gov

 Molecular Environmental Science Group, Building 203, Room E-165
 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007

 Argonne National Laboratory         phone and voice mail: (1) 630 252 5033
 Argonne IL 60439, USA                                fax: (1) 630 252 9793

 My homepage:    http://cars9.uchicago.edu/~ravel 
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/




More information about the Ifeffit mailing list